Suburban Cook County will join Chicago in banning the sale of dogs, cats and rabbits from large-scale professional breeders, adding to a nationwide movement aimed at cutting off demand from animals bred in so-called puppy mills.

The suburban ban, approved without opposition Wednesday by the County Board, will go into effect in October, five months before a similar ordinance takes effect in the city.

As in Chicago, stores would only be allowed to sell or put up for adoption pets from government shelters, rescue agencies and humane societies. Suburban stores also would be allowed to sell animals from federally licensed breeders with no more than five reproducing female animals. Stores violating the ordinance would face fines of up to $500 per banned sale.

The ban, proposed by Commissioner John Fritchey would affect at least 13 pet stores in the suburbs. The city ban approved last month covered 16 stores in city limits.

Suburbs with home rule powers — typically those with more than 25,000 residents — could opt out of the ban. Not affected by the ordinance is the sale of animals via the Internet, which some of the proposal’s critics said is the source of more pets than stores.

Fritchey said he had “nothing against pet shops but was concerned about inhumane conditions at large breeding operations. “If I cannot regulate them directly because they are out of state, we’re going to try to cut off the demand for those dogs and cats here and, at the same time, reduce the number” that are euthanized at shelters, said Fritchey, D-Chicago.

As was the case in the city, the primary advocate for the ban was Puppy Mill Project founder and President Cari Meyers, who has made it her mission to decry so-called puppy mills that breed large numbers of dogs for profit. Dogs are kept in cramped, unsanitary conditions, and their progeny often suffer physical and psychological defects, she contends.

Some pet store owners and the Chicago Veterinary Medical Association opposed the ordinance. Pet shop owners contended that some large-scale breeders operate humanely and the vet group called the ordinance well meaning but misguided.

“The Chicago Veterinary Medical Association strongly believes that ongoing education of the public is a much more effective method to increase pet owner awareness and bring about the desired positive change necessary to address valid concerns regarding unethical, unscrupulous breeders who are the ultimate problem,” the CVMA said in a statement. “Such breeders are likely to find a way to circumvent the letter of the law and still maintain their pet sales via other avenues.”

Mike Bober, vice president for government affairs of the Washington, D.C.-based Pet Industry Joint Advisory Council that represents breeders, pet store and pet suppliers, recommended that pet stores be able to sell animals from federally licensed breeders without a record of violations that directly affect the well-being of animals.